At present, for marine electromagnetic surveying, a pair of plastic pipes with high strength that extend from an acquisition station and are mutually perpendicular, are adopted as supports for the whole acquisition station and grounding electrode for electric field data acquisition. Couple pole lines are arranged in the plastic pipes and are connected to a central data recorder. Two electric field components (Ex and Ey) that are mutually perpendicular are recorded for a continuous acquisition of time domain electromagnetic field data. Active electric field is recorded when there is a field source activating signal, while the natural electric field is recorded when there is no activation. The data is processed indoors after acquisition.
The above configuration is substantially the same as the magnetotelluric “+” configuring method on earth. However, as the acquisition station is arranged at seabed in deep sea environment, operation is very difficult. Firstly, it is difficult for the orientation of the poles configuration to meet the design requirement. When the directions of the measured electric fields obliquely intersect with the activation direction, especially when two electric fields both form an angle of about 45° with the activation direction, the effective activation signals are both 70% of those under collinear activation. Further, the recorded electric field is disturbed by signal in another direction, so that the recorded electric field deviates from the receiving requirement for collinear activation in theory. Secondly, it is difficult to ensure that each recording board for every field component works normally. Once there is an error, data about one measuring point may be lost, which means severe loss to marine electromagnetic surveying. Further, as the recording is made through single couple pole, the acquisition quality cannot be assessed, and post-improvement cannot be made.